I like the standover height of the 19" frame but I like the top tube length of the 21" frame. The LBS put a longer stem on the 19" and moved the seat back for me to try it out and it felt pretty good. Any opinions as to what is the better way to go. If you need to know, I'm just under 6'4 and inseam is 33"-34".

Check out how the 19" handles with the longer stem versus the 21" with the stock stem. Generally they design 'em to handle best with the stock length stem. The other issue with the 19" is that you generally want to avoid using saddle relocation as a means of changing bike fit to avoid potential issues with your pedal stroke (and knee pain, etc.). I would recommend the 21" for you; that's what I've been fitting people your size on at our shops and no complaints yet.

Stor Mand,
I just traded in a bike on the HardRock Pro last week. I'm 6'1 and the size 21 frame works great! I think the 19 is too small for you. The bike is a tank! That's my 2 cents worth. Happy trails!

bi·cy·cle Pronunciation Key (bskl, -s-kl, -skl) n.
A vehicle consisting of a light frame mounted on two wire-spoked wheels one behind the other and having a seat, handlebars for steering, brakes, and two pedals...
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Since you are coming from road I would say get the bigger frame. There is definately no right answer for mtbikes. I prefer a small frame. I am 6'5 with a 36inch inseam and find my 19" kona too big at times. I ride very technical root gardens that are cluttered with rocks and boulders. A big bike would seriously hinder my riding.

I actually never got 'officially' fitted because I can't believe there is one way. I test road every style of bike possible and found the slacker geometry bikes (Kona Roast / specialized P series etc...) with the compact cockpit to fit me best. Most regular shops would never have recommended the bike I have for me unless they understood the style of riding ...

I posted this reply also in the MTB section.Do disk brakes take a while to get grippy or should they be grippy right off the bat? The 19", that gets used more for demos often, has grippier brakes than the 21" that was just built today. Since I have no experience with disk brakes on bicycles, I thought I'd ask.